To disable cooling flaps or not, The endless debate Options

[JamesM]

I still 100% agree that all of these parts need to be there (just got in this same discussion recently on the samba because alot of people don't understand how critical a fast engine warm up is), but if you want the system working exactly as it should, that lower engine tin also needs to be in place.

I agree here as well. It is one of the points that has always bothered me about running headers on a type 4 is that you loose the lower tin.



After owning a water cooled Vangon for some time though I made an interesting observation. Vanagons also have a lower tin below the pushrod tubes despite having fully jacketed cylinders/no cooling air flow coming down off the heads/cylinders. In that application at least its only purpose is to protect the pushrod tubes.

I cant say what the engineers specifically designed that tin for on the type 4 but its something to think about.

[Superhawk996]

I want to say I appreciate all the civil discussion on this topic.

Unfortunately we’ve sort of reached the point where someone needs to do some instrumented testing to get us out of the realm of speculation on the degree that the flaps are modulating and when. I’m guilty here as I don’t have that data at hand.

Someday I’d love to put a string-pot on the thermostat bellows and the flap rod/lever to get live data on how much it’s moving, at what temps, and what engine loads.

Same for having some thermocouple data directly off the cylinders and the bellows.

Ah . . . Someday. For now I’ve got too many other projects going on but maybe someday.

[930cabman]

I want to say I appreciate all the civil discussion on this topic.

Unfortunately we’ve sort of reached the point where someone needs to do some instrumented testing to get us out of the realm of speculation on the degree that the flaps are modulating and when. I’m guilty here as I don’t have that data at hand.

Someday I’d love to put a string-pot on the thermostat bellows and the flap rod/lever to get live data on how much it’s moving, at what temps, and what engine loads.

Same for having some thermocouple data directly off the cylinders and the bellows.

Ah . . . Someday. For now I’ve got too many other projects going on but maybe someday.

aka LIFE, its a good thing to have many projects, keeps us (reasonably) sharp upstairs

I will fall back on the original design even given extreme heat and extreme cold conditions these machines operate in (most of us do not experience these), a well operating thermostat is the correct answer.

Now, back to Ron, hope he is getting to the bottom of his issue

[Jack Standz]

You must realize that the cylinders in a type iv motor don't heat up (the reason for the t-stat) and cool down evenly, right? Cylinder #3 runs the hottest with a stock system, so much so that #3 is in the high heat danger zone more often and longer and usually shows more wear.

So, running a DTM (down the middle) style cooling tin will keep temperatures more even across the cylinders and can allow more HPs (run higher compression, more ignition advance, etc.).

And, so a DTM setup will reduce motor wear, which is what this topic is all about.

So, if you really want to reduce wear in your type iv motor, you would be running either a DTM or flat fan system anyway. (IMG:style_emoticons/default/stirthepot.gif)

Of course those of us that run higher compression, turn more RPMs, run wild performance cams, modify cylinder heads, have installed higher rate valve springs, added longer stroke cranks, increased the cylinder bores, etc. We do know a few that are like this, right? We really don't care about a little extra wear as we are happy if the motor lasts 50k miles before we're going on to the next iteration of what we are running. And we are just loving it!

BTW, totally run a working t-stat on 914s. But, have been seriously considering a flat fan style cooling system that removes the oil cooler to a remote location and out of the way to reduce impact to cylinder cooling and reduce likelihood of uneven cooling of the cylinders.

[JamesM]

I want to say I appreciate all the civil discussion on this topic.

Unfortunately we’ve sort of reached the point where someone needs to do some instrumented testing to get us out of the realm of speculation on the degree that the flaps are modulating and when. I’m guilty here as I don’t have that data at hand.

Someday I’d love to put a string-pot on the thermostat bellows and the flap rod/lever to get live data on how much it’s moving, at what temps, and what engine loads.

Same for having some thermocouple data directly off the cylinders and the bellows.

Ah . . . Someday. For now I’ve got too many other projects going on but maybe someday.

FYI awesome powder coat lists the temp of their various thermostats however I am not sure if that temp is the temp where they start to expand, finish expanding or if the 85-90c they list is the range for the start and finish of the expansion? (IMG:style_emoticons/default/confused24.gif)

that says nothing of the actual curve and impact of it on the actual angle of the cooling flaps or how it compares to the actual head and oil temps

One could deduce though that given the 85c(185f) listed thermostat temp that VW intended the motor to be warmer than the 160f accelerated wear point mentioned in the studies you posted.

It would be cool to have the data, I am a data junkie as well. A huge timesaver though would be to just leave the thermostats hooked up and let them do their thing. (IMG:style_emoticons/default/biggrin.gif)

[porschetub]

I did a slight mod to the factory mounting bracket and ran a T1 unit back then on my first T4,worked well but full expanded @ a lower temp....but better than not having anything .
IMO the earlier opening made no difference ,I would it again .
Cheers.

[emerygt350]

Here are some data points on flap activity. Drove my son to school this morning (25 miles round trip at 60). Went to work for 10 minutes, drove to the gas station, filled the tank and then drove home 30pmh maybe a mile. When I pulled into the driveway here is the temps and the position of the flaps:




.

[emerygt350]

After I loaded my clubs into the car I headed to the driving range (5 miles at 30mph). Pulled into the parking area and snapped these pics.




Notice the cht and the oil temps

This is a 200c oil temp sender.
All photos taken at idle 900rpm

[Superhawk996]

It would be cool to have the data, I am a data junkie as well. A huge timesaver though would be to just leave the thermostats hooked up and let them do their thing. (IMG:style_emoticons/default/biggrin.gif)

You may appreciate this data which is representative of your situation in the mountains.

From Air Cooled Automotive Engines; J. Mackerle


The important point to note is that you don’t really want cylinder temp going below 70C and how the thermostat prevents that from happening on the decent.

Also note that temp consistency is improved. Higher, more consistent temp = less friction losses.

[Superhawk996]

Here are some data points on flap activity.

(IMG:style_emoticons/default/smilie_pokal.gif) Here’s a challenge should you choose to accept. Get a video (or timelapse) of the flap lever position while driving.

[emerygt350]

I do have a cheap go pro.... Talk about a movie only 914 people would watch...

[JamesM]

Notice the cht and the oil temps

This is a 200c oil temp sender.
All photos taken at idle 900rpm

This is what I was saying about flap control being independent of oil temp. Flaps are in the full hot position and oil has a ways to go still.

Oil temp control has two variables, the air over the cooler controlled by the flaps (unrelated to the state of the oil) and the oil flow through the cooler controlled via pressure which creates some interesting cooling problems related to oil weight and/or the condition of your pressure relieve valve.

[emerygt350]

Notice the cht and the oil temps

This is a 200c oil temp sender.
All photos taken at idle 900rpm

This is what I was saying about flap control being independent of oil temp. Flaps are in the full hot position and oil has a ways to go still.

Oil temp control has two variables, the air over the cooler controlled by the flaps (unrelated to the state of the oil) and the oil flow through the cooler controlled via pressure which creates some interesting cooling problems related to oil weight and/or the condition of your pressure relieve valve.

Not on a 73 with a 200c, the range is super truncated. I'm at 210 before I hit the T in temp. It's over 160f in the second picture. Also notice how the cht isnt that much different however there must be much more heat in the cylinders on the second picture.

[JamesM]

You may appreciate this data which is representative of your situation in the mountains.

That's a great find and does reflect what I have experienced.


I wonder what motor/induction was used here. This all has me thinking about ways to utilizing tuning on modern ECUs to better regulate temperatures. This is something I have implemented to some extent but only focusing on keeping temperatures down. Now im wondering if there are things I can implement to increase temps under cold decel situations as it looks like even with the flaps the cooling is pretty pronounced.

[JamesM]

Here are some data points on flap activity.

(IMG:style_emoticons/default/smilie_pokal.gif) Here’s a challenge should you choose to accept. Get a video (or timelapse) of the flap lever position while driving.

Would be awesome to setup probes to get ambient temp, thermostat temp, and oil temp, along with flap position and map that through entire range.

But probably only a benefit to my curiosity.



and now im having evil thoughts about stepper motors and megasquirt (IMG:style_emoticons/default/headbang.gif)

[wonkipop]

You may appreciate this data which is representative of your situation in the mountains.

That's a great find and does reflect what I have experienced.


I wonder what motor/induction was used here. This all has me thinking about ways to utilizing tuning on modern ECUs to better regulate temperatures. This is something I have implemented to some extent but only focusing on keeping temperatures down. Now im wondering if there are things I can implement to increase temps under cold decel situations as it looks like even with the flaps the cooling is pretty pronounced.

the old cold decel/descent one. its interesting.

my every day 2008 1.8 audi a3 has this one and its quite marked compared to say my 2002 renault sport clio. i take a regular drive up to my uncles farm which has quite a long and high (for australia) ascent (descent). i have noticed the audi notideably cools itself on the descent going off the stock in dash temp guage. i put this down to its direct injection, efficiency factored, emission controls software scenarios. it cools a lot during a descent. its basically switched off entirely on downhills. just coasting on engine compression. zero fueling. the renault isn't ? and does not noticeably cool.

its quite interesting. i don't think you could ever factor that out of a type 4 engine given the cooling mechanism and its inherent design.

[Superhawk996]

Would be awesome to setup probes to get ambient temp, thermostat temp, and oil temp, along with flap position and map that through entire range.

But probably only a benefit to my curiosity.

I used to do a lot of data acquisition. Dewitron’s, Somat’s, V-box, and even basic Campbell data loggers way back in the 90s. Went looking on EBay to see what’s available but nothing cheap. There are a couple Cambell’s for really cheap but data size and sample rates are severely limited (like 128k file size limited - dinosaur technology)

What is built into the megasquirt? I haven’t spent any time in their software. Can they handle thermocouples or do they need to be thermistors?

I’ll keep poking around - I’d really like to find something that could log 10-20 channels at say 1-10hz. But needs to be stupid cheap.

[Superhawk996]

doh. Doublepost

[Superhawk996]

wondering if there are things I can implement to increase temps under cold decel situations as it looks like even with the flaps the cooling is pretty pronounced.

I would think you could get something by running a lean burn and advance timing short of decel fuel shutoff that might help but may be difficult to tune without knock sensors.

That data that I posted is ancient - that book was 1st published in 60’s so I would almost guarantee that was a carbureted engine.

[emerygt350]

Arduinos are cheap and the selection of sensors are pretty good. No data storage issues either.


And I just remembered... I have no idea what my thermostat came off of. My original was dead when I bought the car. I found one on a type4 1.7 (I think) (could be a bus 2.0 I guess) with djet that was laying in my buddies shop. So I may have the cooler opening thermostat?